The privately owned Detroit Bus company is still growing in Detroit after more than 3 years. They provide as needed services that people want. They have no standard routes but can be called like a taxi to pick you up using a phone app that shows where the buses are at any given moment. They drop little old ladies with groceries off at their front door and provide free rides to kids in after school programs.
The Go Bus in Grand Rapids does door-to-door service (for those who can’t get around or have a disabled tag) for I think a flat $7 a ride, but the ride has to be scheduled the previous day, and they won’t make change.